The present invention relates to an improved cleaning composition and method for use with molded shower stalls and molded bathtub appliances.
Regulations were imposed on the hospitality industry at the city, county, state, and/or federal level regarding non-slip features for shower stall and bathtub floors. Shortly thereafter the industry moved away from use of traditional non-slip deterrents such as glued down appliquxc3xa9s and non-skid removable mats Appliquxc3xa9s resulted in hard-to-clean floors due to their high profile, and edges where soil and detritus accumulated and adhered to the adhesive portion of the appliquxc3xa9s. The efficacy of non-skid mats was necessarily dependant upon the guests"" use of same. In the event a guest elected not use the mat, legal claims for alleged injuries resulting from slips and falls might nevertheless be pursued.
Thereafter, molded shower stalls and tub units came into widespread use within the hospitality industry. The floor assemblies of such molded units typically contained embossments or ridges, with ridges eventually winning out, to provide what was thought to comprise a permanent non-skid surface. Actual use proved otherwise.
Routine cleaning of these molded units altered the original non-skid surface. Abrasive cleansers and abrasive cleaning pads were the cleaning agents of choice. Daily use of such abrasive cleaners eventually eroded away the non-skid ridges, thereby degrading the non-skid properties of the floor.
In response, the industry moved to non-abrasive acids and/or all purpose cleaners. These cleaners appeared to solve the problem. Again, actual use proved otherwise with a new problem emerging.
Over a period of months-to-years, the non-skid areas of the floor gradually xe2x80x9cgrayed out xe2x80x9dand became unsightly. In addition, the valleys between the ridges slowly filled with some sort of accumulation that, once again, degraded the non-slip properties of the floors. In response, the industry periodically used abrasive cleaners, or volatile organic solvents, to remove such unsightly and dangerous accumulations. After removal of the accumulation, non-abrasive cleaners were routinely then used until an unacceptable accumulation again formed.
The industry hoped that periodic use of abrasive cleaners would not degrade the non-skid properties of the molded floors. Once again, however, actual use proved otherwise. The accumulations in these valleys comprised many layers-upon-layers of material, and required hard scouring with abrasives for up to an hour. Such aggressive cleaning again resulted in erosion of the molded ridges. Volatile solvents such as lacquer thinner did not damage the floor, but toxicity and flammability concerns limited the use of such solvents. Moreover, with the inception of state and federal occupational safety and health programs such as OSHA and NIOSH, strict personal protective equipment and ventilation standards made use of such volatile solvents untenable. As a result, use of lacquer thinner has virtually disappeared from this milieu.
For the past 20-30 years, company after company has submitted cleaning products to the hospitality industry to address this problem. To date, none of the products have proved adequate. As a result, a serious problem still exists today. Guests seeing xe2x80x9cgrayed out xe2x80x9dshower stall and tub floors typically develop a negative perception of both the individual hostelry and of that entire hotel/motel chain. The hospitality industry is intensely aware of these negative perceptions.
As a result, hotel/motel chains and associations regularly inspect their franchisees"" facilities. Penalties are assessed for sub-standard conditions. Dirty, unsightly shower stalls and tubs are second only to linens for assessed penalties. Penalties can result in reduced bonuses for managers, loss of franchise rights, demotions, even dismissal. The severity of these penalties has motivated the hospitality industry to find a cost-effective solution to this decades-old problem.
To date, one of the few viable approaches uses yet another abrasive. This particular product uses a jeweler""s rouge, which greatly reduces the wear-down of the ridges, but can take hours for complete cleaning of the non-skid surfaces. And, bottom line, though minimized, degradation still occurs.
A new approach is needed which comprises a 2-pronged attack using a single cleaning formulation. First, that formulation must comprise a non-abrasive cleaner that can effectively remove the afore-described accumulation. Second, the formulation must facilitate a preventative maintenance program whereunder once-cleaned units and new units do not experience this problem. Applicant""s cleaning composition and method squarely meet both requirements.
Applicants"" novel invention comprises a composition and a method to clean shower stall floors and bathtub floors. Applicant""s cleaning composition is formed by combining a first solvent, a second solvent, a third solvent, a first surfactant, and a second surfactant. Applicant""s first solvent comprises a polar solvent having a dielectric constant xcex5 of at least 15.0, and preferably at least 30.0. Applicant""s second solvent comprises a non-polar solvent having a dielectric constant xcex5 less than 3.0. Applicant""s third solvent comprises one or a plurality of ester compounds. Applicant""s first surfactant is preferably a nonionic surfactant having an HLB of between about 7 and about 10. Applicant""s second surfactant is preferably a nonionic surfactant having an HLB of between about 11 and about 15.
Applicant has found that the undesirable xe2x80x9cgrayxe2x80x9d areas disposed on the floors of shower stalls and bathtubs comprises oligomeric/polymeric residues containing entrapped particulate matter. These oligomeric/polymeric residues are formed over time from soap oils, bath oils, and body oils. Applicant""s cleaning method comprises depolymerizing these oligomeric/polymeric residues to form lower molecular weight compounds. This depolymerization is effected by the polar solvent component of Applicant""s cleaning composition.
These lower molecular weight are then dissolved in the second solvent and/or third solvent component of Applicant""s cleaning composition. This solvent mixture containing the dissolved lower molecular weight compounds is emulsified in water using the first surfactant and/or second surfactant. That emulsified solvent is then rinsed away using water.
In addition, Applicant has found that depolymerization of the oligomeric/polymeric resides releases the entrapped particulate matter. That released particulate matter is then also emulsified in water using the first surfactant and/or second surfactant, and rinsed away.
Applicant has found that the above-described accumulation of unsightly material in the non-skid valleys of molded shower/tub floors is not merely simple soil and/or dirt. Quite to the contrary, Applicant has discovered that this agglomerate actually comprises a layered build-up of soap oils, bath oils, and body oils. These various organic compounds oligomerize/polymerize over time upon exposure to ambient air. By oligomerization, Applicant means the formation of higher molecular weight compounds from lower molecular weight compounds, wherein the higher molecular weight compounds comprise liquids, viscous liquids, and semi-solid materials. By polymerization, Applicant means the formation of high molecular weight compounds from lower molecular weight compounds, wherein the higher molecular weight materials comprise solid materials.
The resulting layers of oligomers and/or polymers entrap particulates, including dirt, soils, incompletely polymerized oils, and the like. Applicant has discovered that such oligomers/polymers, including the entrapped particulates, comprise the xe2x80x9caccumulationxe2x80x9d discussed above.
Applicant has further discovered that these oligomeric/polymeric materials, with their entrapped particulates, chemically and/or mechanically bond to the polymeric coating used on the floor portions of shower stall and tub units. Applicant has developed a cleaning composition and method to remove these undesirable oligomeric/polymeric materials without degrading the molded shower/tub floor or the polymeric coating disposed on same.
Applicant""s cleaning formulation is formed from mixing a first solvent, a second solvent, a third solvent, a first surfactant, and a second surfactant. These components can be mixed in any order using conventional equipment and techniques.
Applicant""s first solvent comprises a polar solvent having a dielectric constant xcex5 of at least 15.0. Preferably, this first solvent has a dielectric constant of 30.0 or greater. As those skilled in the art will appreciate, the dielectric constant of a substance, often called the permittivity, is the ratio of the electric displacement D to the electric field strength E when an external field is applied to the substance. The dielectric constant values recited below comprise the relative permittivities, which comprise the ratios of actual permittivities to the permittivity of a vacuum, and hence, are dimensionless numbers.
Applicant has discovered that when his cleaning formulation contains at least one solvent having a dielectric constant of at least 15.0, that cleaning formulation cleaves the above-described oligomeric/polymeric residues into lower molecular weight components. Such lower molecular weight materials can then be dissolved in solvents of low to medium polarity, such as Applicant""s second and third solvents.
Suitable compounds for use as Applicant""s first solvent include butyrolactone (xcex5=39.0), N-methylpyrrolidone (xe2x80x9cNMPxe2x80x9d) (xcex5=32.55), N,N-dimethylformamide (xe2x80x9cDMFxe2x80x9d) (xcex5=38.25), acetone (xcex5=20.7), methyl ethyl ketone (xcex5=18.5), cyclohexanol (xcex5=16.4), and mixtures thereof. xcex3-Butrolactone, NMP, and DMF are preferred.
Applicant""s first solvent is added to Applicant""s formulation in an amount between about 25 and about 40 weight percent. Preferably, the first solvent is added in an amount between about 30 and about 35 weight percent.
Applicant""s second and third solvents dissolve, among other things, the lower molecular weight compounds resulting from depolymerization of oligomeric/polymeric residues. Applicant""s second solvent is a non-polar organic compound having a dielectric constant xcex5 less than 3.0. In order to control the flash point of the formulation, Applicant""s first solvent preferably comprises hydrocarbon compounds having at least six (6) carbon atoms. Organic solvents such as hexane (xcex5=1.89), heptane (xcex5=1.92), octane (xcex5=1.95), nonane (xcex5=1.97), decane (xcex5=1.99), and the like may be used. Naturally-occurring compounds are preferred. Terpene-derived compounds such as limonene (xcex5=2.37), the pinenes (xcex5=2.18xe2x88x922.50), the terpinenes (xcex5=2.27xe2x88x922.45), terpinolene (xcex5=2.29), and mixtures thereof, are preferred. Cold pressed natural oils, such as orange oil, obtained from pressing fruits, i.e. oranges, contain mixtures of terpene-derived, unsaturated hydrocarbon compounds having pleasant odors, and hence, are most preferred.
Applicant""s second solvent is added to Applicant""s formulation in an amount between about 5 weight percent and about 25 weight percent. Preferably, the second solvent is added to Applicant""s formulation in an amount between about 6 weight percent and about 20 weight percent.
Applicant""s third solvent comprises one or more saturated and/or unsaturated ester compounds. Many of these esters are derived from soy bean oil. As those skilled in the art will appreciate, such esters are formed by reacting one mole of a carboxylic acid and one mole of an alcohol with the removal of one mole of water. 
Tables I and II set forth preferred carboxylic acids, i.e. the R1 component, and preferred alcohols, i.e. the R2 component, respectively, used to form the preferred ester compounds comprising Applicant""s third solvent.
Applicant""s third solvent is preferably formed from one or more of the ester compounds formed using the ingredients recited in Tables I and II. Methyl palmitate, methyl stearate, methyl oleate, methyl linoleate, methyl linolenate, and mixtures thereof are most preferred. Applicant""s third solvent is added in an amount between about 15 weight percent and about 35 weight percent.
Applicant""s formulation is further formed by adding a first surfactant which, among other things, emulsifies and solubilizes the individual components of Applicant""s cleaning composition. Anionic, cationic, amphoteric, or nonionic surfactants may be used. Nonionic surfactants are preferred. Nonionic surfactants having a Hydrophilic Lipophilic Balance (xe2x80x9cHLBxe2x80x9d) between about 7 and about 10 are most preferred. Such nonionic surfactants may comprise linear polyoxyethylene (xe2x80x9cPOExe2x80x9d)/alkyl ethers, POE sorbitan esters, and mixtures thereof.
Alkyl polyoxyethylene ethers may be described as a POE X Alkyl Ether, wherein the X represents the average number of repeat units of ethylene oxide reacted with an alkyl alcohol to form the ether. For example, POE 10 stearyl ether is formed by reacting, on the average, 10 ethylene oxide molecules with one stearyl alcohol molecule. Those skilled in the art will appreciate that the polymerization reaction of ethylene oxide cannot be precisely controlled. Therefore, the actual distribution of oxyethylene units for any given average may be quite wide.
Table III sets forth commercially available surfactants suitable for use as Applicant""s first surfactant. Applicant""s first surfactant is added to the cleaning composition in an amount between about 10 weight percent and about 20 weight percent.
Applicants"" formulation is further formed by adding a second surfactant. Applicant has found that this second surfactant, among other things, emulsifies the first solvent and the second solvent, and aids in emulsifying the solubilized lower molecular weight compounds resulting from depolymerization of the above-described oligomeric/polymeric residues.
Anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, and mixtures thereof may be used. Nonionic surfactants having an HLB between about 10 and about 15 are preferred. Such nonionic surfactants may comprise linear polyoxyethylene (xe2x80x9cPOExe2x80x9d)/alkyl ethers, POE sorbitan esters, and mixtures thereof.
Sorbitan is formed by the cyclodehydration of sorbitol. Thus, sorbitan has multiple hydroxyl groups that can serve as reaction points for forming ethers or esters. Sorbitan ester surfactants are available as monoesters, diesters, triesters, and sesquiesters. In addition, the actual distributions of ether side chains formed by reaction of sorbitan with ethylene oxide may be quite wide.
Table IV sets forth commercially available products which may be used as Applicant""s second surfactant. Applicant""s second surfactant is added to the cleaning composition in an amount between about 10 weight percent and about 20 weight percent.
The following examples are presented to further illustrate to persons skilled in the art how to make and use the invention and to identify presently preferred embodiments thereof. These examples are not intended as limitations, however, upon the scope of the invention, which is defined only by the appended claims.